Nowadays, with increasing development of high technology industries, electronic devices are widely used in our daily lives. For most electronic devices, a variety of electronic lighting elements are used to generate light signals to notify the user. For example, a red light signal is shown if an electric hot-water heater is cooking water. After the water contained in the electric hot-water heater has been boiled, the red light signal is switched to a green light signal to notify the user that the water has been boiled and is now feasible to drink. The examples of using electronic lighting elements in electronic devices to notify the users are too numerous to be enumerated.
Recently, the electronic device using a single electronic lighting element to generate the light signal is not satisfactory. The electronic devices using multi-stage electronic lighting modules to generate multi-stage light signals. A multi-stage electronic lighting module contains numeral electronic lighting elements, in which one or more of the electronic lighting elements selectively illuminate to create different light signals or different lighting effects, thereby generating many kinds of prompts. For example, a multifunction peripheral has multiple light signals to indicate different working modes. When the multifunction peripheral is switched from a working mode to another working mode, different number of light signals will be generated. For example, when the multifunction peripheral is in a scanner mode, a light signal is generated; when the multifunction peripheral is in a copier mode, two light signals are generated; and when the multifunction peripheral is in a printer mode, three light signals are generated. Moreover, the multi-stage electronic lighting module is applicable to computer peripheral devices such as mice, keyboards or other input devices.
During operation of the multi-stage electronic lighting module, the light beams emitted by different electronic lighting elements are possibly interfered with each other. In other words, the light beams emitted by an electronic lighting element may be scattered such that portions of light beams are projected to adjacent electronic lighting element. Under this circumstance, a so-call light leakage problem occurs. Hereinafter, the structure of the multi-stage electronic lighting module of an input device and the light leakage problem occurred in the electronic lighting elements will be illustrated in more details with reference to FIG. 1.
FIG. 1 is a schematic cross-sectional view of an input device having a multi-stage indicating lamp according to the prior art. The input device 1 principally comprises a case 14 and an electronic lighting module. A plurality of case perforations 141 are formed in the case 14. The electronic lighting module comprises a printed circuit board 10, a first electronic lighting element 11, a second electronic lighting element 12, a light guide post member 13 and multiple partition plates 15. The light guide member 13 comprises a light guide platform 131 and multiple light guide posts 132. The first electronic lighting element 11 and the second electronic lighting element 12 emit first light beams B1 and second light beams B2, respectively.
In the input device 1 having a multi-stage indicating lamp, the first electronic lighting element 11 and the second electronic lighting element 12 are disposed on the printed circuit board 10 and aligned with the light guide posts 132 of the light guide member 13. Consequently, the light beams B1 and B2 emitted by the electronic lighting elements 11 and 12 are guided by the light guide posts 132 of the light guide member 13. The upper terminals of the light guide posts 132 are inserted into corresponding case perforations 141 of the case 14. Every two adjacent light guide posts 132 are separated by a partition plate 15. When the light beams B1 and B2 emitted by the electronic lighting elements 11 and 12 are guided by respective light guide posts 132 of the light guide member 13 and exited from the case perforations 141, the partition plates 15 may block the light beams B1 and B2 from being scattered to adjacent light guide posts 132. That is, the partition plates 15 used in the input device 1 may facilitate avoiding or minimizing the light leakage problem. The conventional input device 1, however, still has some drawbacks. For example, since the light guide platform 131 of the light guide member 13 is made of transparent material, some of the light beams B1 and B2 are not blocked by the partition plates 15 and possibly scattered out of the light guide platform 131. Under this circumstance, the light leakage problem still occurs.
Therefore, there is a need of providing an input device having a multi-stage indicating lamp for minimizing the light leakage problem.